Clearer Skies Over China: Reconciling Air Quality, Climate, and Economic Goals

4. Primary Air Pollutant Emissions of Coal-Fired Power Plants in China

4 Primary Air Pollutant Emissions of Coal-Fired Power Plants in China Yu Zhao 4.1 Introduction Coal is the primary energy source for Chinese power generation. As shown in figure 4.1, thermal power has maintained a large share of both electricity output and installed capacity (82% and 76%, respectively, for 2005). For many years, thermal power has been fueled predominantly by coal with very small amounts by oil or gas. During 2000–2007, the period in which the Chinese power sector developed fastest within the past 30 years, coal consumption by power plants increased from 560 to 1300 million tons (Mt) according to official statistics. As shown in figure 4.2, in recent years the share of total coal consumption by the power sector has remained around 50%. Investment in clean energy such as wind power and hydropower has also increased, but the overall Chinese power structure is still dominated by coal-fired generation, and this domination will continue in the foreseeable future. As the largest coal-consuming sector, power generation has been considered the most important source of atmospheric pollutant emissions and thereby of regional air pollution. A series of studies has been conducted on Chinese emission inventories using top-down methods, that is, using industry-wide average characteristics and data. These studies indicate that the power sector accounts for 31–59% of national anthropogenic emissions of sulfur dioxide, SO2 (Streets et al. 2003; van Aardenne et al. 2005; Ohara et al. 2007; Klimont et al. 2009; Zhang et al. 2009), 21–44% of nitrogen oxides, NOX (Hao, Tian, and Lu 2002; Streets et al. 2003; van Aardenne et al. 2005; Ohara et al. 2007; Zhang et al. 2007a; Klimont et al. 2009; Zhang et al. 2009), and 9% of particulate matter, PM (Zhang et al. 2007b; Lei, Zhang, and Streets 2011). In treating power generation as a single sector in a larger emission inventory framework, these studies have either applied uniform emission factors across the sector or referenced domestic emission standards to estimate emissions. They 162 Chapter 4 generally have ignored differences in technology and fuel characteristics among power units of different types, which have very different emission characteristics. Moreover, most studies have not reflected the rapid increase of coal consumption and electricity generation since the year 2000, and thus their results are less applicable for current policy analysis. Under increasing environmental pressure, the Chinese government chose the coalfired power sector as the most important target for abating atmospheric emissions during 2006–2010, the period of the 11th Five-Year Plan (11th FYP). Power plants thus faced more stringent environmental regulations related to siting and operations. A B Figure 4.1 Chinese power sector development during 1980–2010. (A) Electricity output. (B) Installed capacity. Primary Air Pollutant Emissions of Coal-Fired Power Plants in China 163 Two main measures were implemented: (1) all new thermal power units, as well as most existing ones, were required to install flue gas desulfurization (FGD) systems; and (2) most small units with low energy efficiency, estimated to total about 59 gigawatts (GW), were gradually shut down. In order to provide a detailed picture of emissions for scientific research and policy analysis, this study uses an innovative unit-based method to explore current and future emissions of Chinese coal-fired power plants. We also consider the effects of currently implemented and prospective emission control policies. These results are integrated into the wider emission inventory study described in chapter 6, which in turn is applied in the integrated project’s atmospheric simulations described in chapter 7. 4.2 Methods 4.2.1 Unit-Based Methodology Our study covers 31 provinces and province-level administrative units of mainland China; Hong Kong, Macao, and Taiwan are not included. The pollutants examined in this chapter are SO2, NOX, and PM. In contrast to prior studies, emissions are estimated through a bottom-up methodology based on individual combustion units. Figure 4.2 Coal consumption by the Chinese power sector during 1990–2007. 164 Chapter 4 Figure 4.3 Flow chart of the unit-based bottom-up methodology. (We are also of course interested in CO2 generated by electric power plants, but as explained in chapter 6, we use a concurrent bottom-up study by the author and colleagues to estimate base year CO2 emissions for all sectors [Zhao, Nielsen, and McElroy 2012]. The economic model of chapter 9 then scales CO2 emissions under the...